To Test Offset Accuracy - HP 54520 Series Service Manual

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Chapter 3: Testing Performance
To test offset accuracy
To test offset accuracy
This test checks the offset accuracy.
Specification +(1.25% of channel offset + 2% of full scale)
Equipment Required
Equipment Critical Specifications Recommended
Model/Part
Power Supply 0.5 V to 2 Vdc, +1 mV accuracy HP 6114A
Cable BNC HP 105034
Adapter BNC (f) to dual banana (m) HP 1251-2277
Procedure
Press Recall then cir tosetthe oscilloscope to default conditions, then
set the following parameters.
Menu {hardkey)} Function/Parameter Setting
Horizontal Setup "repetitive
Display {mode} avg
# of avg 32
Entry Fine {on}
Use the banana-to-BNC adapter to connect the BNC cable between the power
supply and channel 1 input.
Use the following table for steps 4 through 7.
Volts/div Position Supply Tolerance Limits
minimum maximum
200 mV 2.00000 V 2.00 V 457 mV 1.943 2,087 V
100 mV 1,00000 V 1.00 428.5 mV 0.9715 1.0285 V
50 mV 500.000 mV 500 mV 414,25 mV 485.75 514,25 mV
Press the channel number key (bottom row) and set the v/div range and position
from the first line of the table.
Set the supply voltage to 2.00 V as in the first line.
Readjust the position so the trace is as close to the horizontal center line of the
graticule as possible after it has settled (averaging complete).
Read the position voltage. It should be at its original setting, within the limits given
in the table. Record the reading in the Performance Test Record.
Repeat steps 4 through 7 for the other lines in the table.
With the channel keys (bottom row) set the active channel of£ and the next on.
Repeat steps 2 through 10 for any untested channels, setting the parameters of the
channel being tested where appropriate.
lf the test fails
Offset errors can be caused by the need for self-calibration. Perform self-calibration, 0. vertical
cal, (see chapter 4, "Calibrating and Adjusting') before troubleshooting the instrument.